A three-dimensional stacked body semiconductor device is being developed in order to provide high density and high-performance. As one of methods of forming the three-dimensional stacked body, there is a method in which chips are stacked so as to overlap each other and electrodes provided in the chips are directly connected to each other. A through-silicon-via (TSV) is used as an electrode in this method. In the related art, convex portions made of metal with a low melting point, that is, bumps are formed at end parts of the TSV, and the bumps are melted so as to bond to each other. This method is called a micro-bump method.
In this micro-bump method, there are cases where TSVs adjacent to each other may become short-circuited by protrusions from the bumps formed when the bumps are melted. This issue limits the minimum pitch between the TSVs on the chip surface which hampers miniaturization of stacked semiconductor devices.